This invention relates to acoustic sources for transmitting acoustic energy at low and medium frequencies and more particularly to a cavitating parametric underwater acoustic source for efficiently transmitting acoustic energy at low and medium frequencies.
Present techniques or systems for transmitting acoustic power at low and medium frequencies require large projectors usually equipped with unreliable pressure compensating devices. Furthermore, such a conventional source has very low efficiency for transmitting a wide band of low frequencies as the transducers or transducer elements used resonate at a single frequency. Non-cavitating parametric acoustic sources also have quite low efficiency to transmit acoustic power at low and medium frequencies as there is only a small amount of non-linearity resulting from changes in velocity of sound with pressure changes in the medium. Thus it is desirable to have an acoustic source which will transmit acoustic energy at low and medium frequencies with great efficiency and wherein one can use small and rugged transducers or transducer elements which can be electrically energized at high frequencies.